There is an increasing demand to color a battery, such as, e.g., a lithium ion secondary battery, to match the appearance and color thereof to those of a device such as an electric device to which the battery is to be mounted. To give a stately feeling and/or a high-grade feeling, such a device is colored black in many cases. In such a case, the battery thereof is also colored black in many cases.
To color a battery black or other colors, there are means for, e.g., coloring a resin layer used as a battery packaging material or providing a print layer under a base material resin layer.
For example, as a battery packaging material having a colored layer, the following packaging materials are known:
1) a packaging material having a structure in which a base material layer, an adhesive agent layer, a metal foil layer, and a thermal adhesive resin layer are laminated in this order, and a pigment is added to any one of the base material layer, the adhesive agent layer, and the metal foil layer (see Patent Document 1: Japanese Unexamined Laid-open Patent Application Publication No. 2011-054563);
2) a battery outer packaging material having a layer containing a black material such as a carbon material, etc. (see Patent Document 2: Japanese Unexamined Laid-open Patent Application Publication No. 2011-096552); and
3) a battery packaging material having a structure in which a white resin film base material is laminated on a surface of a battery outer packaging material and a white ink layer is laminated on a surface of the white resin film base material (see Patent Document 3: Japanese Unexamined Laid-open Patent Application Publication No. 2009-289533).